Photographic developing tank



Aug. 6, 1946. MORSE 2,405,160

PHOTOGRAPHIC DEVELOPING TANK Filed March 27, 1943 dOHN F. MORSE Patented Aug. 6, 1946 UNITED STATES PATENT OFFICE PHOTOGRAPHIC DEVELOPING TANK John F. Morse, Hudson, Ohio Application March 27, 1943, Serial No. 480,865

Claims.

The present invention relates to apparatus for use in the development of photographic films or plates, it being the object of the invention to perfect a form of apparatus which may be used for the development of negatives in daylight, thereby dispensing with the usual practice of carrying out such operations in a dark room. It is one of the purposes of the invention. to design a form of light-proof holder or container which can be manipulated so that negatives may be developed, fixed and washed without the necessity of opening the holder. The holder may be placed successively in the several baths necessary for the development of the film, so that from the time the film is placed inside of the holder it is not removed or exposed until the development is completed.

It is a further object of the invention to provide a self-contained, light-proof holder which may be supported on the rim of a tank for holding the treating solution and which will drain quickly and rapidly so that the holder is effectively emptied and the holder may be immediately transferred to a second tank for further treatment. The holder is so designed that, by raising and lowering it while in the solution, the liquid within the holder may be thoroughly agitated.

These and other objects will be realized by the invention, the best-known and preferred form of which is shown and described herein, it being understood that the invention is not limited to the details of construction illustrated but may be varied and modified within the scope of the invention as set forth in the appended claims.

In the drawing in which the best-known form of the invention is illustrated:

Fig. 1 is a plan view of the complete developing assembly, a portion of the top of the holder being broken away to disclose the interior construction;

Fig. 2 is a vertical section on the line 2-2 of Fi 1;

Fig. 3 is a detailed section on the line 3-3 of Fig. 1; and

Fig. 4 is a section on the line 4-4 of Fig. 3.

In the drawing the tank for holding the bath is indicated by the numeral I. This tank may hold either the developing solution, the fixing solution, or water for washing the negatives. The holder is indicated at 2. It is composed of an opaque body portion l and two laterally extending wings 3 designed to rest upon the upper edge of the tank I, so that the lower edge of the holder is spaced above the floor of the tank. The holder is of slightly smaller external dimension than the internal dimension of the tank and in order to insure that the holder is spaced all around from the walls of the tank, the holder may be provided with projections, here illustrated as vertical ribs 4 located at intervals about the exterior of the holder.

The base of the holder is provided with a plurality of lattice-like grids, here shown as four in number and indicated by the numeral 5. As shown each grid is formed of a plurality of inclined louvers or bars 6, which in the adjacent grids are inclined in oppositedirections and overlapped so that the multiplicity of grids form an effective light seal closing in the bottom of the holder. These grids are held in place against lugs 1 formed internally of the holder above its lower edge by a series of bolts 8 and the group of grids is fastened together as a unit by a central screw 9. Except at lugs formed where the fastening means are located, the grids are spaced 7 apart to prevent any trapping of the solutions between contacting surfaces of the grids. This is shown in the sectional area of the grids in Fi 2.

It will be seen that while the grid construction eifectively battles all light rays so that no light may enter through the bottom of the holder, the inclined surfaces of the louvers permit the liquid bath to drain freely and quickly from the bottom of the holder. Also when it is desired to agitate the bath the holder may be raised and lowered in the bath and the bath will surge freely into and out of the holder and around the negatives. The grid work provides a multiplicity of vertically arranged circuitous passages which allow quick drainage of the holder.

The negatives are mounted in frames i2 suspended within the holder by lateral arms I3 which rest upon the upper side of the wings 3. A holder is constructed to support as many of these frames as may be desirable.

The upper edge of the holder is formed with a surrounding upright flange IS, on which the opaque cover I6 is seated. The cover is formed with a depending flange 18 which surrounds the flange I5 and with an interior wall l9 which fits loosely on the inside of the flange [5. This arrangement provides a light seal around the top of the tank, but in order to permit air to flow into and out of the holder the outer wall and top of the flange I 5 are formed with a plurality of spacing projections, here shown as ribs 20. This 3 arrangement facilitates the free flow of air into and out of the holder around the edge of the cover while the liquid is running into or draining from the holder.

Two sliding metal clips or fasteners 22 are mounted on the top of the cover, being held in position by the plate 23. A downwardly and laterally extending wing 25 on each clip is designed to seat in a recess 26 on the under side of the wing 3 when the fasteners are'moved into locking position. In Fig. 2 one of the clips is shown in engagement with the underside of the wing 3 while the other is free.

In using this device the undeveloped negatives are 1oaded in the frames 52 and the frame placed within the holder in the dark room, the cover applied and locked in place. The interior of the holder is now light-proof and the holder is then taken out of the dark room and placed in the tank containing the developing solution, which runs freely into the interior of the holder through the grids 5. The operator may, by holding the wings 3, raise and lower the holder while in the tank and pump the developing solution into and out of the holder. As the holder extends above the upper rim of the tank he does not get his hands into the solution. When time for development has passed the holder is lifted from the developing tank, and perm tted to drain, which it does immediately due to the arrangement of the grids at the bottom of the holder.

The holder is then moved to a washing tank, to the fixing tank I and then to the final washing tank. The developing process is now completed, the cover removed and the negative frames removed for drying. All of the developing operations, as will be seen, may be performed out of the dark room. The operations are therefore more rapid and efficient than with the older practice of performing all the operations in room.

What is claimed is:

1. An apparatus for use in the development of negatives comprising an open-top tank for con.- taining a developing solution, a holder for he negatives, said holder loosely fitting the interior of the tank and having lateral wings the underside of which rest upon the walls of the tank so that the holder is suspended therein, a negativeholding frame having lateral projections which rest upon the ledges formed by the upper sides of the wings, and passages at the bottom of the holder for permitting the liquid therein to pass into the interior of the holder, but to exclude light therefrom, and air vents at the top of the holder arranged to exclude light.

2. An apparatus for daylight development of negatives comprising a tank, a negative holder, said holder having an opaque body portion and an opaque removable cover, lateral wings on the holder adapted to seat on the upper wall of the tank to support the holder therein, and negative holding frames within the holder having arms resting upon the inner surfaces of the wings, light-excluding air passages at the top of the tank, and light-excluding passages at the bottom of the holder for permitting fluid to enter and drain from the interior of the holder, said last named passages being formed by a plurality of grids having oppositely directed inclined louver in each grid overlapping the passages in an adjacent grid.

3. An apparatus for daylight development of negatives comprising a tank, a negative holder, said holder having an opaque body portion and an opaque removable cover, lateral Wings on the holder adapted to seat on the upper walls of the tank to support the holder therein, negative holding frames within the holder having arms resting upon the inner surfaces of the Wings, circuitous light-excluding air passages around the edge of the cover, and light-excluding passages at the bottom of the holder for permitting fluid to enter and drain from the interior of the holder, said last named passages being formed by a plurality of grids having oppositely directed inclined louvers in each grid overlapping the passages in an adjacent grid.

4. An apparatus for the daylight development of negatives comprising an open top tank containing a treating solution, and a light-proof negative holder comprising four opaque walls, two opposite walls being provided at the top of the holder with lateral wings adapted to rest upon the upper edge of the tank and to provide interior bays upon which a negative frame may be supported with its contents within the holder, an upstanding wall around the top of the negative holder, an opaque cover over the negative holder, said cover having a downwardly turned rim about its edge, said rim having a tongue and groove engagement with the upstanding wall, spacing means in the tongue and groove engagement to provide a light-sealing air passage between the cover and the negative holder, and a a dark grid at the base of said negative holder, said grid being provided with a multiplicity of circuitous vertical passages to permit the free circulation of the treating solution into and out of the negative holder as the negative holder is raised and lowered into the tank.

5. An apparatus for the daylight development of negatives comprising an open top tank containing a treating solution, and a light-proof negative holder comprising four opaque walls, two opposite walls being provided at the top of the holder with lateral wings adapted to rest upon the upper edge of the tank and to provide interior bays upon which a negative frame may be supported with its contents within the holder, an upstanding wall around the top of the negative holder, an opaque cover over the negative holder, said cover having a downwardly turned rim about its edge, said rim having a tongue and groove engagement with the upstanding wall, spacing means in the tongue and groove engagement to provide a light-sealing air passage between the cover and the negative holder, and a grid at the base of said negative holder, said grid being pro- Vided with a multiplicity of circuitous light excluding passages formed by superposed tiers of reversely arranged inclined walls.

JOHN F. MORSE. 

